Autoantibody profiling of patients with autoimmune thyroid disease using a new multiplexed immunoassay method

Background: It has been proposed that only anti-thyroid-peroxidase ( TPOAb) and not anti-thyroglobulin (TgAb) antibodies should be assayed in the diagnosis of autoimmune thyroid disease (AITD). Methods: We analyzed the thyroid autoantibody profile with a multiplex bead array system, which allows simultaneous measurement of thyroid autoantibodies (FIDIS, BioMedical Diagnostics, Marne La Vallee, France). A total of 151 AITD patients ( 111 Hashimoto's thyroiditis and 40 Graves' disease) and 414 control patients were recruited to the study. Results: The diagnostic sensitivity of TPOAb was greater than that of TgAb in both Hashimoto's thyroiditis ( 91.9% vs. 82.5%) and Graves' disease ( 82.5% and 52.5%, respectively), whereas the diagnostic specificity was similar ( 92.7% for TPOAb and 92.4% for TgAb). Conclusions: The presence of isolated positivity for TgAb in 6% of the Hashimoto's thyroiditis patients indicates that the use of only the TPOAb test does not guarantee sufficient diagnostic sensitivity. In the light of recent findings relating to the pathogenetic role of TgAb and TPOAb in Hashimoto's thyroiditis, knowledge of the autoantibody profile could allow the identification of sub- groups of patients with a different degree of activation of the thyroid autoimmune process.